GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  CONTIGFREE (9)

NAME

contigmalloc, contigfree - manage contiguous kernel physical memory

CONTENTS

Synopsis
Description
Implementation Notes
Return Values
Examples
Diagnostics
See Also

SYNOPSIS


.In sys/types.h
.In sys/malloc.h void *
.Fo contigmalloc unsigned long size struct malloc_type *type int flags vm_paddr_t low vm_paddr_t high unsigned long alignment vm_paddr_t boundary
.Fc void
.Fo contigfree void *addr unsigned long size struct malloc_type *type
.Fc

DESCRIPTION

The contigmalloc function allocates size bytes of contiguous physical memory that is aligned to alignment bytes, and which does not cross a boundary of boundary bytes. If successful, the allocation will reside between physical addresses low and high. The returned pointer points to a wired kernel virtual address range of size bytes allocated from the kernel virtual address (KVA) map.

The flags parameter modifies contigmalloc ’s behaviour as follows:
M_ZERO
  Causes the allocated physical memory to be zero filled.
M_NOWAIT
  Causes contigmalloc to return NULL if the request cannot be immediately fulfilled due to resource shortage.

Other flags (if present) are ignored.

The contigfree function deallocates memory allocated by a previous call to contigmalloc.

IMPLEMENTATION NOTES

The contigmalloc function does not sleep waiting for memory resources to be freed up, but instead actively reclaims pages before giving up. However, unless M_NOWAIT is specified, it may select a page for reclamation that must first be written to backing storage, causing it to sleep.

RETURN VALUES

The contigmalloc function returns a kernel virtual address if allocation succeeds, or NULL otherwise.

EXAMPLES

void *p;
p = contigmalloc(8192, M_DEVBUF, M_ZERO, 0, (1L << 22),
    32 * 1024, 1024 * 1024);

Ask for 8192 bytes of zero-filled memory residing between physical address 0 and 4194303 inclusive, aligned to a 32K boundary and not crossing a 1M address boundary.

DIAGNOSTICS

The contigmalloc function will panic if size is zero, or if alignment or boundary is not a power of two.

SEE ALSO

malloc(9), memguard(9)
Search for    or go to Top of page |  Section 9 |  Main Index


Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.